USB HUB for M4 Controller

[Adithya_Jayaram]

Hi we're using STM32L412RBT6P controller for our development process and NUCLEO-L412RB-P is the evaluation board we've chosen, and the selected controller has  USB 2.0 full-speed crystal less solution
with LPM and BCD and according to the requirement we need a 4 Port USB HUB and the HUB should have one upstream and 4 downstream ports, please suggest the proper USB HUB  from your product line which suites the requirement which I've mentioned, if it's not there in your product line then please suggest us the compatible HUB for the controller we're using.

Thanks,

Adithya 

[waclawek.jan]

The USB in 'L412 is Device only, i.e. it is not capable of being Host and you can't connect a Upstream port of Hub to it.

Maybe you want to elaborate on your requirements and also have a look at some basic tutorial of how USB works.

JW

[Adithya_Jayaram]

Our requirement is, We're developing a control panel and 4 port USB HUB is the integral part of this control panel, it helps to build the interconnection between the presently used (which is trackball) and future USB peripherals and the HUB will be connected to the controller(STM32L412RBT6P) via USB 2.0 peripheral.

[waclawek.jan]

So, you say, that presently you have connected a trackball to STM32L412 via USB?

JW

[Adithya_Jayaram]

Check the system diagram, this Control panel is the redesign previously they've used the different controller and multiple number of PCBS which made the system cost high, so we're redesigning it and planning to use the STM32L412RBT6P  as our controller for this development, so before confirming the controller wanted to make sure about the USB. also as mentioned above USB HUB helps to build the interconnection between the presently used (which is trackball and Optional Quart Keyboard) and future USB peripherals and the HUB will be connected to the controller(STM32L412RBT6P) via USB 2.0 peripheral.

[waclawek.jan]

You really should start with doing some reading of how USB works.

USB is asymmetrical: you have a Host (typically PC), which controls Devices (connected through Hubs).

The USB on 'L412 is Device-only. You cannot control other Devices from it.

Note, that in the OTG-USB in some STM32 (higher-end 'L4, starting from 'L47x; 'F4xx, 'F7xx, 'H7xx) while capable of being either Host or Device, still may not support a Hub (due to a hardware limitation).

JW

[Adithya_Jayaram]

Thanks JW, will definitly do the more reading and research about USB communication, team have clarified that the STM32L412RBT6P, trackball and Qwarty keypad will be connected to the downstream port of the HUB and Upstream is connected to the main board.

[waclawek.jan]

> STM32L412RBT6P [...] will be connected to the downstream port of the HUB

Then the 'L4 is Device and it is OK for it to be connected to the Hub.

JW